The projections from the dorsal lateral geniculate nucleus (LGN) and medial interlaminar nucleus (MIN) to areas 17 and 18 of visual cortex in the fox will be examined using first orthograde and then retrograde neuroanatomical tracing techniques. Initially, the technique of transneuronal autoradiography following application of radioactive tracers to the retina of one eye will be used to determine the overall a pattern and extent of the projection to visual cortex from these two thalamic relay nuclei. It is expected that direct visual thalamic projections will be seen to both areas 17 and 18. Retrograde transport of the enzyme horseradish peroxidase (HRP) injected into either area 17 or area 18 will then be used to confirm the direct nature of these projections and to more precisely determine the cortical target (area 17, area 18 or both) of each of these two thalamic nuclei. The HRP results should also allow us to specify the soma size and dendritic characteristics of the specific cells within the LGN and MIN which project to these cortical areas.